Method and system for wellbore debris removal

ABSTRACT

The present disclosure relates to a method and apparatus for removing debris from a wellbore, comprising providing a surface pump for supplying a fluid stream, a work string fluidly connected to the surface pump for passing the fluid stream from the surface pump, a tool body fluidly connected to the work string, including a plurality of tool body exit ports for passing the fluid stream from the work string into an annular space of the wellbore, and a collection chamber fluidly connected to and downhole from the tool body, for accepting uphole flow of the fluid stream including entrained wellbore debris. The fluid stream including entrained wellbore debris is drawn upward through the collection chamber, and the fluid stream from the work string and the fluid stream from the collection chamber are passed into the annular space of the wellbore. In addition, a cartridge may be inserted into the tool body.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to the following U.S. Non-Provisionalpatent application Ser. No. 15/671,213 filed Aug. 8, 2017 and isincorporated by reference in its entirety.

FIELD OF THE INVENTION

The present disclosure relates to the field of well drilling and, moreparticularly to a method and system for wellbore debris removal.

BACKGROUND OF THE INVENTION

During operations to drill and complete an oil or gas well, debris suchas metal cuttings, broken metal or composite parts, pieces of rock,sand, and other unwanted material may obstruct a wellbore and preventaccess required for further operations in the wellbore. The debris mayhave accumulated in the wellbore due to normal drilling operations ordue to the milling of objects such as packers, plugs or stuck tools.

A common method for wellbore debris removal involves a bottom-holeassembly (“BHA”) employing reverse circulation of pumped fluid, a nozzleor narrow fluid passageway, and a debris collection chamber. Usingnormal circulation, pumped fluid flows from a pump at the surfacethrough a central pipe bore, such as through a work string and anydistally adjoining equipment, exiting the central pipe bore at thebottom of the wellbore, and returning up the annular space between thewall of the wellbore and the work string or adjoining equipment to thesurface. In contrast, when using reverse circulation, the supplied fluidis diverted out of the central pipe bore and into the annular spacebefore the fluid reaches the bottom of the wellbore. The diverted fluidflows through one or more nozzles or narrow fluid passageways thataccelerate the fluid and induce a pressure drop as the diverted fluidflows toward the annular space. The diverted fluid flows down theannular space to the distal end of a debris collection assembly. Thisfluid flow agitates debris near this distal end, entrains the debris,and carries the debris into a collection chamber that includes checkvalves and a screen to capture the debris. In the vicinity of the upperportion of the collection chamber, the debris-entrained fluid passesthrough a screen or filtering mechanism. The filtering mechanism cleansthe fluid of debris to a certain extent and the cleaned fluid moves onthrough passageways to the annular space and down to the distal end of adebris collection assembly. When the operation is complete, the bottomhole assembly is pulled to the surface and the collection chamber isemptied of collected debris.

In current reverse circulation systems, diverted fluid flows through oneor more nozzles or narrow fluid passageways that accelerate the fluidand induce a pressure drop, creating suction to urge debris-entrainedreturn fluid toward the low pressure area generated by the nozzle. Thissuction effect draws debris into a collection chamber for capture andsubsequent extraction.

However, haphazard placing of a low pressure, high velocity flow area inrelation to return fluid effuse ports or passages—for example, in theannular space—achieves inefficient suction. Further, currentimplementations emphasize creating a decrease in pressure and not onmaking any purposeful use of the kinetic energy inherent in increasedfluid velocity. For example, in situations involving clogged wellboresand few or one collection chamber segments, more kinetic energy toentrain debris would be helpful. Another case of annular space fluidvelocity playing a key role occurs in the event the BHA is deployed withthe work string being comprised of coiled tubing rather than straighttubular segments. The nature of coiled tubing operations make it likelythat the collection chamber would have very limited segments andadditionally that the BHA might not have a means of rotation.

In addition, suction achieved using a low pressure flow area in theannular space cannot be adjusted for wellbore conditions or suboptimalfluid pumping capacity.

As the foregoing illustrates, what is needed in the art is an improvedsuction apparatus that can be customized to a particular drillingsituation while remaining strong enough to withstand wellboreoperations.

BRIEF SUMMARY OF THE INVENTION

The disclosed subject matter provides for a method and apparatus forremoving debris from a wellbore.

In light of the above, the present disclosure provides a method andapparatus for removing debris from a wellbore, comprising providing asurface pump for supplying a fluid stream, a work string fluidlyconnected to the surface pump for passing the fluid stream from thesurface pump, a tool body fluidly connected to the work string,including a plurality of tool body exit ports for passing the fluidstream from the work string into an annular space of the wellbore, and acollection chamber fluidly connected to and downhole from the tool body,for accepting uphole flow of the fluid stream including entrainedwellbore debris. The fluid stream including entrained wellbore debris isdrawn upward through the collection chamber, and the fluid stream fromthe work string and the fluid stream from the collection chamber arepassed into the annular space of the wellbore. In addition, a cartridgemay be inserted into the tool body.

The disclosed subject matter allows the suction to be achieved using alow-pressure flow area in the annular space to be adjusted for wellboreconditions or suboptimal fluid pumping capacity, allowing customizationto a particular drilling situation while remaining strong enough towithstand wellbore operations.

BRIEF DESCRIPTION OF THE DRAWINGS

The present subject matter will now be described in detail withreference to the drawings, which are provided as illustrative examplesof the subject matter so as to enable those skilled in the art topractice the subject matter. Notably, the figures and examples are notmeant to limit the scope of the present subject matter to a singleembodiment, but other embodiments are possible by way of interchange ofsome or all of the described or illustrated elements and, further,wherein:

FIG. 1 illustrates the processes of normal circulation and reversecirculation as used in wellbore debris removal.

FIG. 2 illustrates an exemplary embodiment of the present invention.

FIG. 3 illustrates a more detailed exterior side view of an exemplaryembodiment of the present invention.

FIG. 4 depicts a side section view of a tool body of the presentinvention.

FIG. 5 depicts an underneath, bottom-up exterior view of the tool bodyof the present invention.

FIG. 6 depicts an overhead, top-down exterior view of the tool body ofthe present invention.

FIG. 7 depicts a side exterior view of an insertable cartridge of thepresent invention.

FIG. 8 depicts a side section view of the insertable cartridge of thepresent invention.

FIG. 9 depicts an overhead, top-down exterior view of the insertablecartridge of the present invention.

FIG. 10 depicts an underneath, bottom-up exterior view of the insertablecartridge of the present invention.

FIG. 11 depicts section views of the tool body and insertable cartridgeof the present invention.

FIG. 12 depicts a side exterior view of key portions of the boreholeassembly of the present invention.

FIG. 13 depicts a more detailed view of a portion of FIG. 12,

FIG. 14 depicts a side external view of significant portions of anassembled borehole assembly.

FIG. 15 depicts a half cross section corresponding to the external viewof FIG. 14.

FIG. 16 depicts an external perspective view of an exemplary embodimentof the present invention.

FIG. 17 depicts a side exterior view of an integrated tool body of asecond exemplary embodiment of the present invention.

FIG. 18 depicts a side view cross section of the integrated tool body ofthe second exemplary embodiment of the present invention.

FIG. 19 depicts a top-down view of the integrated tool body of thesecond exemplary embodiment of the present invention.

FIG. 20 depicts a bottom-up view of the integrated tool body of thesecond exemplary embodiment of the present invention.

FIG. 21 depicts a cross section of a third exemplary embodiment of thepresent invention.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The detailed description set forth below in connection with the appendeddrawings is intended as a description of exemplary embodiments in whichthe presently disclosed process can be practiced. The term “exemplary”used throughout this description means “serving as an example, instance,or illustration,” and should not necessarily be construed as preferredor advantageous over other embodiments. The detailed descriptionincludes specific details for providing a thorough understanding of thepresently disclosed method and system. However, it will be apparent tothose skilled in the art that the presently disclosed process may bepracticed without these specific details. In some instances, well-knownstructures and devices are shown in block diagram form in order to avoidobscuring the concepts of the presently disclosed method and system.

For clarity, neither the wellbore itself or wellbore debris are shown inthe accompanying drawings. In this description, “Venturi effect” refersto the effect created when fluid passes through a restriction,specifically the resultant change in pressure and velocity of the fluid.“Nozzle” and “Venturi nozzle” refer to, for the purposes of thisdescription, geometrical characteristics, including a narrowedrestriction, of a fluid passageway that are designed with the intent tocontrol fluid flow in such a way as to optimize the Venturi effect.Thus, for the purposes of this description, the “Venturi nozzle” is arestrictive fluid passageway formed and integrated directly into a toolbody and matching insertable cartridge.

In the present specification, an embodiment showing a singular componentshould not be considered limiting. Rather, the subject matter preferablyencompasses other embodiments including a plurality of the samecomponent, and vice-versa, unless explicitly stated otherwise herein.Moreover, applicants do not intend for any term in the specification orclaims to be ascribed an uncommon or special meaning unless explicitlyset forth as such. Further, the present subject matter encompassespresent and future known equivalents to the known components referred toherein by way of illustration.

Although the method and system for wellbore debris removal heredisclosed have been described in detail herein with reference to theillustrative embodiments, it should be understood that the descriptionis by way of example only and is not to be construed in a limitingsense. It is to be further understood, therefore, that numerous changesin the details of the embodiments of this disclosed process andadditional embodiments of this method and apparatus for removing debrisfrom a wellbore will be apparent to, and may be made by, persons ofordinary skill in the art having reference to this description. It iscontemplated that all such changes and additional embodiments are withinthe spirit and true scope of this disclosed method and system as claimedbelow.

FIG. 1 depicts BHAs in schematic form, and illustrates the processes ofnormal circulation and reverse circulation as used in wellbore debrisremoval.

Using normal circulation, pumped fluid enters a central pipe bore at A,flows through the central pipe bore or central passageway (B), and exitsthe central pipe bore at the bottom of the wellbore (C). After exiting,the fluid returns up the annulus, the annular space between the wall ofthe wellbore and the work string or adjoining equipment to the surface.

Using reverse circulation, pumped fluid also enters a central pipe boreat A and flows through the central pipe bore or central passageway (B).At C, the supplied fluid is diverted out of the central pipe bore andinto the annulus or annular space. At D, the diverted fluid continuesdown the annulus or annular space to the bottom of the wellbore (E). AtE the fluid flow agitates nearby debris, entrains the debris, andcarries the debris up the wellbore (F) and into a collection chamber (G)that includes check valves and a screen or filtering mechanism tocapture the debris. At H the cleaned fluid exits to the annular space,where some fluid flows up toward the surface and some fluid joins fluidfrom the surface and continues down the annular space to the bottom ofthe wellbore at E.

Reverse circulation wellbore debris removal is a necessary alternativeto normal circulation wellbore debris removal in various commonsituations. For example, surface pumping capacity may be inadequate topropel debris or small particulate matter all the way to the surface.Capturing debris in a removable collection chamber provides a means foreffective removal. Some wells have poor circulation characteristics,making normal fluid return infeasible. With poor circulation and lowfluid volumes, reverse circulation solves the problem as only a smallamount of fluid over a relatively short distance is required to collectand remove debris.

FIG. 2 illustrates an exemplary embodiment 100 of the present invention.In particular, FIG. 2 shows an exterior side view that includes fluidpower unit 101 as part of a bottom hole assembly (“BHA”). The BHAincludes top sub adapter 120, fluid power unit 101, bottom sub adapter130, collection chamber 170, and shoe 160. The BHA is inserted into awellbore on a work string 122 in order to execute wellbore debrisremoval operations.

In operation, fluid from a surface pumping system travels through workstring 122 and top sub adapter 120 and into tool body 102. The fluidflows through internal passageways within tool body 102 and exits toolbody 102 into the annular space of a wellbore. Once the fluid has exitedtool body 102 into the annular space, a portion of the fluid travelsdownward within the annular space, between the wall of the wellbore andthe exterior of the BHA, to the area below shoe 160. In the area belowshoe 160, the flowing fluid agitates nearby debris, entraining debrisinto the fluid. Suction generated in fluid power unit 101 powers thefluid stream containing entrained wellbore debris, carrying this debrisinto debris collection chamber 170, where it remains for subsequentextraction. The filtered fluid is drawn back into tool body 102 to becommingled with fluid from the surface and exits tool body 102 againthrough exit ports 104. This cycle continues for the duration of thewellbore debris removal operation, creating a loop through which fluidmay pass multiple times during the operation.

FIG. 3 illustrates a more detailed exterior side view of tool body 102of exemplary embodiment 100, including exit ports 104 and tool bodylower threads 118. Exemplary embodiment 100 uses six circumferentiallyequally spaced nozzles, and thus FIG. 3 depicts three exit ports 104 onthe visible half of the exterior of tool body 102.

While exemplary embodiment 100 uses six nozzles, any number of nozzlesdistributed around the lateral circumference of the cartridge could beutilized to deliver circumferentially distributed fluid flow from toolbody 102 into the annular space. Kinetic energy in fluid velocity in theannular space becomes more important as a debris agitation and clearingmechanism in situations with clogged wellbores and few or one collectionchamber segments. For example, in a horizontal wellbore, debris maysettle to the lower portion of the wellbore while leaving the upperportion relatively clear of debris. In such a case tool body 102 andother parts of the BHA may abut annular debris on the lower portion ofthe BHA. A circumferentially distributed flow can agitate debrisabutting the lower portion of the BHA in addition to generating thesuction drawing debris into the BHA.

Another case of annular space fluid velocity playing a key role occursin the event the BHA is deployed on coiled tubing, with work string 122being comprised of coiled tubing rather than straight tubular segments.The nature of coiled tubing operations makes it likely that collectionchamber 170 would have very limited segments and additionally that theBHA may not have a means of rotation. Again, in such a case, anengineered, tuned fluid velocity in the annular space combined with thecircumferentially distributed flow maximizes distribution and deliveryof fluid energy and resultant debris agitation and recovery.

FIG. 4 depicts a side section view of tool body 102 of exemplaryembodiment 100. Tool body central return fluid passageway 112 isdisposed along the longitudinal axis of tool body 102. Cartridge cavity152 and tool body cartridge guiding keyway 154 are inside the upperportion of tool body 102. Tool body 102 also includes at least one toolbody Venturi nozzle tube 107 leading to an exit port 104. Tool bodycartridge guiding keyway 154 ensures accurate insertion of a cartridgeinto cartridge cavity 152 so that each fluid passageway within thecartridge aligns with a corresponding tool body Venturi nozzle tube 107in tool body 102. Fluid exits cartridge cavity 152 through tool bodyVenturi nozzle tube 107, mixing area 116, and exit port 104 into theannular space.

Tool body 102 must make a proper connection with other components inexemplary embodiment 100. Referring again to FIG. 4, tool body upperthreads 114 are relatively fine female threads and are designed to befine, as opposed to coarse, in order to increase strength. The tool bodyupper threads 114 of tool body 102 are in fact threads commonlyincorporated into downhole overshot tools used in fishing operations.Top sub adapter 120 (shown in FIG. 2) attaches to tool body 102 via toolbody upper threads 114. At the lower portion of tool body 102, tool bodylower threads 118 connect to bottom sub adapter 130 (shown in FIG. 2).Bottom sub adapter 130 is used to cross over to other threads insegments of collection chamber 170.

FIG. 5 depicts an underneath, bottom-up exterior view looking along thelongitudinal axis of tool body 102 from below, proximal to tool bodylower threads 118. Exit ports 104 are visible as well as a clear andunobstructed view through tool body central return fluid passageway 112.In a wellbore debris removal operation, fluid would be simultaneouslyflowing toward the viewer from exit ports 104 (between the tool exteriorand wellbore wall, not shown) and away from the viewer into tool bodycentral return fluid passageway 112.

FIG. 6 depicts an overhead, top-down exterior view looking along thelongitudinal axis of tool body 102 from above, proximal to tool bodyupper threads 114. Along this longitudinal axis there is a clear andunobstructed view through tool body central return fluid passageway 112as well as a view into tool body Venturi nozzle tube 107. Cartridgecavity and tool body cartridge guiding keyway 154 are also shown.

FIG. 7 depicts a side exterior view of insertable cartridge 150.Insertable cartridge 150 includes cartridge guiding keyway 156.Cartridge guiding keyway 156 functions in conjunction with tool bodycartridge guiding keyway 154 and a key, not shown, but known to thoseskilled in the art, to ensure accurate insertion of insertable cartridge150 into cartridge cavity 152, alignment of fluid passageways ofinsertable cartridge 150 and tool body 102, and resistance to rotationor torsion that could impair said alignment.

Cartridge top sub-matching profile 155 has a shape that matches thebottom end of top sub adapter 120 where top sub adapter lower threads124 screw into tool body 102 and tighten down upon insertable cartridge150. Cartridge top sub-matching profile 155 has a downwardly-slopingbevel to provide a self-centering profile and ensure equal distributionof compressive force for sealing. Upper cartridge seal groove 157 andlower cartridge seal groove 158 are designed to house elastomeric seals,such as O-ring type seals, and prevent flow leakage, minimal as it mightbe, between cartridge cavity 152 and insertable cartridge 150. A varietyof sealing elements and designs could be applied in exemplary embodiment100 by those skilled in the art, including but not limited tometal-to-metal sealing of fluid passageways in insertable cartridge 150and tool body 102.

FIG. 8 depicts a side section view of insertable cartridge 150, showingparts through which fluid flows. Fluid supplied from the surface flowsinto tapered Venturi entrance port 108 and down through cartridgeVenturi nozzle tube 106. Fluid returning from the bottom of the BHAflows upward into cartridge central fluid passageway 113 and into returnfluid re-integration tube 110. Fluid in return fluid re-integration tube110 flows downward to merge with the motive fluid from the surfaceflowing downward in cartridge Venturi nozzle tube 106.

Plug 144 may be inserted into insertable cartridge 150 to block fluidfrom the surface from flowing directly downward through the center ofinsertable cartridge 150 via cartridge central fluid passageway 113.Plug 144, when inserted into insertable cartridge 150, enables reversecirculation to occur, forcing fluid from the surface through taperedVenturi entrance ports 108, cartridge Venturi nozzle tubes 106, and exitports 104, down the annular space, and then back upward through thecenter of shoe 160, collection chamber 170, tool body central returnfluid passageway 112, cartridge central fluid passageway 113, and intoreturn fluid re-integration tube 110. In the absence of plug 144,reverse circulation does not occur and fluid power unit 101 does notperform as designed.

The bottom side of plug 144 is formed with plug dome cavity 143, acurved surface designed to smooth return fluid flow and reduceturbulence as the return fluid makes the turn from cartridge centralfluid passageway 113 and enters return fluid re-integration tubes 110.Different shapes may be utilized on the bottom side of plug 144 in placeof plug dome cavity 143.

As an alternative to plug 144, and as is well known by those skilled inthe art, a ball (not shown) may be “dropped,” that is, inserted into thefluid stream supplied from the surface. The fluid stream will carry theball into insertable cartridge 150 and seat at the upper opening of toolcartridge central fluid passageway 113 to block the flow, remainingseated in place due to a differential pressure present whenever fluid issupplied from the surface.

FIG. 9 depicts an overhead, top-down exterior view looking along thelongitudinal axis of insertable cartridge 150 and through tool cartridgecentral fluid passageway 113, without plug 144 being inserted into placeto obstruct the view. The upper surface of cartridge top sub-matchingprofile 155 is proximal to the observer. Distal from tapered Venturientrance port 108 are cartridge Venturi nozzle tube 106 and the lowerend of return fluid re-integration tube 110.

FIG. 10 depicts an underneath, bottom-up exterior view looking along thelongitudinal axis of insertable cartridge 150 and through tool cartridgecentral fluid passageway 113, without plug 144 being inserted into placeto obstruct the view. Cartridge lower central seal groove 140 isproximal to the observer. The proximal end of cartridge Venturi nozzletube 106 contains combined fluid from return fluid re-integration tube110 flow and fluid flow supplied from the surface.

FIG. 11 depicts section views of tool body 102 and insertable cartridge150 of exemplary embodiment 100, showing how insertable cartridge 150inserts into cartridge cavity 152 of tool body 102. As described above,cartridge guiding keyway 156 functions in conjunction with tool bodycartridge guiding keyway 154 and a key, not shown, but known to thoseskilled in the art, to ensure accurate insertion of insertable cartridge150 into cartridge cavity 152, alignment of fluid passageways ofinsertable cartridge 150 and tool body 102, and resistance to rotationor torsion that could impair said alignment. FIG. 10 also depicts toolbody upper threads 114 and tool body lower threads 118.

FIG. 12 depicts a side exterior view of key portions of the BHA. Thisview includes tool body 102, top sub adapter 120, top sub adapterfishing neck 121, top sub adapter large diameter end 123, and bottom subadapter 130. A break is shown from bottom sub adapter 130 to the lowerend of collection chamber 170 and collection chamber threads 171. Thisview shows the BHA in an assembled state, including fluid power head 101and tool body 102. Exit ports 104 are shown, indicating where fluidexits tool body 102.

FIG. 13 depicts a more detailed view of a portion of FIG. 12, includingportions of tool body 102, top sub adapter 120, and bottom sub adapter130 in an assembled state. Insertable cartridge 150 is shown insertedinto position, receiving compressive force from top sub adapter 120which is threaded into position. Plug 144 is shown in place below topsub adapter 120 and thus enables reverse circulation while blockingdirect fluid flow between top sub fluid dispersion cavity 128 and toolbody central return fluid passageway 112. Bottom sub adapter 130 is alsoshown threaded into position at the bottom end of tool body 102.

Fluid supplied from a surface pump passes through top sub adapterfishing neck 121 and into top sub fluid dispersion cavity 128, a spaceof larger inside diameter than the uphole portion of top sub adapter120, allowing fluid to flow toward tapered Venturi entrance ports 108.Fluid next flows into tapered Venturi entrance port 108 and down throughcartridge Venturi nozzle tube 106, where high-velocity and low pressurepersist, and where fluid from the surface is merged with flow comingfrom return fluid re-integration tube 110.

Tool body Venturi nozzle tube 107 adjoins cartridge Venturi nozzle tube106. The merged fluid flows continue downward into tool body Venturinozzle tube 107 and then into mixing area 116 before leaving tool body102 at exit ports 104 to continue downward into the annular space. Forclarity in illustration, tool body Venturi nozzle tube 107 is shown ashaving the same diameter as cartridge Venturi nozzle tube 106. However,in practice, tool body Venturi nozzle tube 107 may have the samediameter as cartridge Venturi nozzle tube 106 where it abuts cartridgeVenturi nozzle tube 106 and conically flare to the same diameter asmixing area 116. Alternatively, tool body Venturi nozzle tube 107 can bemade the same diameter, over its entire length, as mixing area 116,resulting in a potential efficiency gain while simplifying sealing andfitting of insertable cartridge 150 to tool body 102.

Exemplary embodiment 100 shows a simple Venturi nozzle for simplicityand ease of manufacturing, and for durability in harsh downholeconditions. More intricate designs are known in the art, such as, forexample, a discrete nozzle that emits fluid into the tapered inletportion of a Venturi tube or a basic carburetor-style intake protrudinginto the narrowed high velocity Venturi area. The insertable cartridgesystem disclosed herein readily permits incorporation of more intricateVenturi-based pumping mechanisms.

FIG. 14 depicts a side external view of significant portions of anassembled BHA. FIG. 14 includes top sub adapter 120, with a breakindicating a shortened view, tool body 102, bottom sub adapter 130,collection chamber 170, with a break indicating a shortened view, and atthe bottom, collection chamber threads 171.

FIG. 15 depicts a half cross section corresponding to the external viewof FIG. 14. FIG. 15 shows significant portions of exemplary embodiment100, previously described, in an operation-ready state and connected tothe BHA.

FIG. 16 depicts an external perspective view of exemplary embodiment 100with three key assembled components: fluid power head 101, top subadapter 120, and bottom sub adapter 130. By changing connecting threadsor dimensions, each of fluid power head 101, top sub adapter 120, andbottom sub adapter 130 may be adapted to meet a variety of downhole workstring and BHA needs.

Thus, debris may be removed from a wellbore by providing work string122, tool body 102, insertable cartridge 150, and collection chamber170; drawing a fluid stream including entrained wellbore debris upwardthrough collection chamber 170; and passing the fluid stream up fromcollection chamber 170, into cartridge central fluid passageway 113,through cartridge Venturi nozzle tubes 106 and through tool body exitports 104 into the annular space of the wellbore.

In exemplary embodiment 200, fluid power head 101, tool body 102, andinsertable cartridge 150 are replaced by integrated tool body 202. FIG.17 depicts a side exterior view of integrated tool body 202, and FIG. 18depicts a side view cross section of integrated tool body 202. Requiredconnections to other BHA components are made via tool body upper threads214, again utilizing a fine thread for strength, and tool body lowerthreads 218, in the same manner as in exemplary embodiment 100.

FIG. 19 depicts a top-down view of integrated tool body 202, proximal totool body upper threads 214, looking along the longitudinal axis throughtool body central return fluid passageway 212. FIG. 20 depicts abottom-up view of integrated tool body 202, proximal to tool body lowerthreads 218, looking along the longitudinal axis through tool bodycentral return fluid passageway 212. Nozzle 216 indicates the orificethrough which motive fluid will flow before exiting to the annular spaceat exit port 204. Similar to exemplary embodiment 100, exemplaryembodiment 200 uses six circumferentially equally spaced nozzles 216 andexit ports 204. While exemplary embodiment 200 uses six nozzles, anynumber of nozzles distributed around the lateral circumference of toolbody 202 could be utilized to deliver circumferentially distributedfluid flow from tool body 202 into the annular space.

Exemplary embodiment 200 utilizes reverse circulation much likeexemplary embodiment 100, utilizing a plug at the upper, larger diameterportion of central return fluid passageway 212 indicated by location 220(not shown, but similar to plug 144 above) or ball drop method toexecute the reverse circulation. However, in exemplary embodiment 200,low pressure inducing suction is generated in the annular space. Inparticular, exemplary embodiment 200 does not mix fluid supplied fromthe surface and the return fluid within integrated tool body 202.Instead, fluid supplied from the surface passes through a cavityinterior to tool body upper threads 214 and flows down to exit tool body202 at high velocity through exit ports 204. Thus, low pressure and highvelocity flow occur in the vicinity of exit ports 204. Return fluidflow, having traveled up through the center of the BHA, exits integratedtool body 202 via return fluid exit ports 244 into the annular space,drawn toward exit ports 204 due to low pressure occurring proximal toexit ports 204. Thus, in exemplary embodiment 200, fluid supplied fromthe surface and return fluid mix near exit ports 204, in the annularspace.

With straight bores through integrated tool body 202, exemplaryembodiment 200 may be more easily manufactured than exemplary embodiment100. Return fluid exit ports 244 and exit ports 204 may be located, inrelation to each other, as deemed most effective in generating suction.

Exemplary embodiment 200 also has the advantage of optionalball-drop-selectable nozzle closure. Such ball-drop-selectable nozzleclosure acts to modify fluid stream flow and debris removal force at thepoint accelerated fluid exits nozzles 216 and exit ports 204.

As noted above, exemplary embodiment 200 makes use of a plurality ofnozzles 216 distributed around the 360-degree circumference ofintegrated tool body 202. During a debris removal operation, a widevariety of circumstances may be encountered, and the unseen downholeconditions may present unusual challenges to crew conducting theoperation. By nature, the unknowns in oil and gas operations incentivizetrial-and-error experimentation. Considering the unknown nature ofwellbore debris obstructions, and taking into account pressure and flowdata, the crew may wish to alter fluid flow within the tool during anoperation. Fluid flow may be altered by inserting appropriately-sizedballs into the supplied fluid at the surface, executing a “ball drop”according to industry parlance. The ball will go to the entrance of thenozzle 216 that is experiencing the highest flow rate of the pluralityof nozzles 216, and serve to obstruct the particular nozzle 216 for theduration of the debris removal operation. Additional balls may bedropped to obstruct more nozzles. Closure of one or more nozzles 216will alter the higher velocity flow in proximity to the tool andpotentially alter vorticity and turbulence at the distal end of theadjacent assembly. Reynolds numbers in the annular space would increase.Thus turbulence and debris agitation along the annular space and at thedistal end where debris is pulled into collection chamber 170 may bemodified to suit a particular drilling situation.

The optional ball-drop-selectable nozzle closure, described above,enables effective wellbore debris removal operations when, for whateverreason, available surface pumping capacity is less than optimal. Forexample, and strictly hypothetically, assume that optimal surfacepumping capacity is 3 barrels per minute, but the available surfacepumping capacity is only 2 barrels per minute, and flow normally goesthrough six nozzles at the downhole tool. The tool would not functionoptimally with this reduced pumping capacity. However, on-siteadjustments may enable adequate function. In this example, two ballscould be dropped, closing two nozzles, or one third of the flow. Such aclosure would allow wellbore debris removal, albeit with lesserefficiency than designed or planned, making use of sub-optimal availablesurface pumping capacity. With time being of the essence in virtuallyall oil and gas operations, the disclosed subject matter's ability toadjust in real time to sub-optimal conditions and execute an operationprovides significant value to an operator facing unpredictablereal-world circumstances.

Thus, debris may be removed from a wellbore by providing work string122, tool body 202, and collection chamber 170; drawing a fluid streamdown from the top of the wellbore through nozzle tubes 216 and exitports 204, drawing a fluid stream including entrained wellbore debrisupward through collection chamber 170; and passing the fluid stream upfrom collection chamber 170, into tool body 202, and through returnfluid exit ports 244 into the annular space of the wellbore.

FIG. 21 depicts a cross section of exemplary embodiment 300. Exemplaryembodiment 300 is similar in fluid-flow function to exemplary embodiment200. However, exemplary embodiment 300 employs an insertable cartridge350 that is inserted into tool body 302 in similar fashion as exemplaryembodiment 100's insertable cartridge 150. Insertable cartridge 350 isshown inserted into place inside the upper portion of tool body 202.

In exemplary embodiment 300, flows occur in the same manner as exemplaryembodiment 200, with the suction effect concentrated in the annularspace and with no mixing of return fluid and motive fluid inside toolbody 202. In particular, in exemplary embodiment 300, low pressure andhigh velocity flow occur in the vicinity of exit ports 204. Return fluidflow, having traveled up through the center of the BHA, exits integratedtool body 202 via return fluid exit ports 244 into the annular space,drawn toward exit ports 204 due to low pressure occurring proximal toexit ports 204. Thus exemplary embodiment 300 combines the flow andsuction of exemplary embodiment 200 with the insertable cartridge designof exemplary embodiment 100. Exemplary embodiment 300 may also be usedwith the optional ball-drop-selectable nozzle closure described abovewith reference to exemplary embodiment 200.

Thus, debris may be removed from a wellbore by providing work string122, tool body 202, insertable cartridge 350 inserted into tool body302, and collection chamber 170; drawing a fluid stream down from thetop of the wellbore through nozzle tubes 216 and exit ports 204, drawinga fluid stream including entrained wellbore debris upward throughcollection chamber 170; and passing the fluid stream up from collectionchamber 170, into insertable cartridge 350, and through return fluidexit ports 244 into the annular space of the wellbore.

In light of the above, the present disclosure provides a method andapparatus for removing debris from a wellbore, comprising providing asurface pump for supplying a fluid stream, a work string fluidlyconnected to the surface pump for passing the fluid stream from thesurface pump, a tool body fluidly connected to the work string,including a plurality of tool body exit ports for passing the fluidstream from the work string into an annular space of the wellbore, and acollection chamber fluidly connected to and downhole from the tool body,for accepting uphole flow of the fluid stream including entrainedwellbore debris. The fluid stream including entrained wellbore debris isdrawn upward through the collection chamber, and the fluid stream fromthe work string and the fluid stream from the collection chamber arepassed into the annular space of the wellbore. In addition, a cartridgemay be inserted into the tool body.

The disclosed subject matter allows the suction achieved using a lowpressure flow area in the annular space to be adjusted for wellboreconditions or suboptimal fluid pumping capacity, allowing customizationto a particular drilling situation while remaining strong enough towithstand wellbore operations.

All references, including publications, patent applications, andpatents, cited herein are hereby incorporated by reference to the sameextent as if each reference were individually and specifically indicatedto be incorporated by reference and were set forth in its entiretyherein.

The detailed description set forth herein in connection with theappended drawings is intended as a description of exemplary embodimentsin which the presently disclosed subject matter may be practiced. Theterm “exemplary” used throughout this description means “serving as anexample, instance, or illustration,” and should not necessarily beconstrued as preferred or advantageous over other embodiments.

This detailed description of illustrative embodiments includes specificdetails for providing a thorough understanding of the presentlydisclosed subject matter. However, it will be apparent to those skilledin the art that the presently disclosed subject matter may be practicedwithout these specific details. In some instances, well-known structuresand devices are shown in block diagram form in order to avoid obscuringthe concepts of the presently disclosed method and system.

The foregoing description of embodiments is provided to enable anyperson skilled in the art to make and use the subject matter. Variousmodifications to these embodiments will be readily apparent to thoseskilled in the art, and the novel principles and subject matterdisclosed herein may be applied to other embodiments without the use ofthe innovative faculty. The claimed subject matter set forth in theclaims is not intended to be limited to the embodiments shown herein,but is to be accorded the widest scope consistent with the principlesand novel features disclosed herein. It is contemplated that additionalembodiments are within the spirit and true scope of the disclosedsubject matter.

What is claimed is:
 1. An apparatus for removing debris from a wellbore,comprising: a work string, for passing a fluid stream from a top of thewellbore; a tool body fluidly connected to the work string, including aplurality of tool body exit ports for passing the fluid stream from thework string into an annular space of the wellbore; a collection chamberfluidly connected to and downhole from the tool body, for acceptinguphole flow of the fluid stream including entrained wellbore debris; anda cartridge, insertable into the tool body, including a cartridgecentral fluid passageway and a plurality of cartridge Venturi nozzletubes distributed around the lateral circumference of the cartridge,wherein each Venturi nozzle tube is fluidly connected to one of theplurality of tool body exit ports, the cartridge Venturi nozzle tubesfor providing suction inside the cartridge, drawing the fluid stream upfrom the collection chamber, into the cartridge central fluidpassageway, through the cartridge Venturi nozzle tubes and through thetool body exit ports into an annular space of the wellbore.
 2. Theapparatus of claim 1, the tool body further comprising a tool bodyVenturi nozzle tube fluidly connected to each tool body exit port. 3.The apparatus of claim 1, further comprising: a top sub adapter, forconnecting the tool body to the work string; a bottom sub adapter, forconnecting the tool body to the collection chamber; and wherein the toolbody further comprises: an upper threaded portion, for connecting thetool body to the top sub adapter; and a lower threaded portion, forconnecting the tool body to the bottom sub adapter.
 4. The apparatus ofclaim 1, further comprising a plug for insertion into the cartridge, forforcing the fluid stream from the work string through the cartridgeVenturi nozzle tubes and preventing the fluid stream from the workstring from flowing directly through the cartridge central fluidpassageway.
 5. The apparatus of claim 4, the plug further comprising ashaped bottom surface for reducing turbulence of fluid flow from thecartridge central fluid passageway.
 6. The apparatus of claim 1, thetool body further comprising a tool body cartridge guiding keyway andthe cartridge further comprising a corresponding cartridge guidingkeyway, for ensuring accurate insertion of the cartridge into the toolbody.
 7. The apparatus of claim 1, wherein the cartridge furthercomprises a cartridge top sub-matching profile having a shape matchingthe bottom of the top sub adapter and a downwardly-sloping bevel, forproviding a self-centering profile and equal distribution of compressiveforce for sealing.
 8. The apparatus of claim 1, the cartridge furthercomprising an upper cartridge seal groove and a lower cartridge sealgroove, for housing seals and preventing flow leakage between thecartridge and the tool body.
 9. The apparatus of claim 1, the cartridgefurther comprising a plurality of return fluid re-integration tubes,wherein each return fluid re-integration tube is fluidly connected to acorresponding tool body exit port and to the central fluid passageway.10. An apparatus for removing debris from a wellbore, comprising: a workstring, for passing a fluid stream from a top of the wellbore; a toolbody fluidly connected to the work string, comprising: a plurality ofnozzles distributed around the lateral circumference of the tool body,each nozzle fluidly connected to a tool body exit port, for passing thefluid stream from the work string into an annular space of the wellbore,and a plurality of return fluid exit ports distributed around thelateral circumference of the tool body, for accepting uphole flow of thefluid stream and passing the accepted uphole flow of the fluid streaminto the annular space of the wellbore; and a collection chamber fluidlyconnected to and downhole from the tool body, for accepting uphole flowof the fluid stream including entrained wellbore debris and passing thefluid stream into the tool body.
 11. The apparatus of claim 10, furthercomprising a plug for insertion into the central return fluid passagewayof the tool body, for forcing the fluid stream from the work stringthrough the tool body nozzles and preventing the fluid stream from thework string from flowing directly through the central return fluidpassageway.
 12. The apparatus of claim 10, further comprising a ball forinsertion into the top of a tool body nozzle, for preventing the fluidstream from the work string from flowing through the tool body nozzle inwhich the ball has been inserted and directing the fluid stream from thework string through the remaining tool body nozzles into the annularspace.
 13. The apparatus of claim 10, further comprising a cartridge,insertable into the tool body, including a cartridge central fluidpassageway and a plurality of cartridge nozzles distributed around thelateral circumference of the cartridge, wherein each nozzle is fluidlyconnected to one of the plurality of tool body exit ports.
 14. Theapparatus of claim 13, further comprising a plug for insertion into thecartridge, for forcing the fluid stream from the work string through thecartridge nozzles and preventing the fluid stream from the work stringfrom flowing directly through the cartridge central fluid passageway.15. A method for removing debris from a wellbore, comprising: providinga work string, for passing a fluid stream from a top of the wellbore; atool body fluidly connected to the work string, including a plurality oftool body exit ports for passing the fluid stream from the work stringinto an annular space of the wellbore; a collection chamber fluidlyconnected to and downhole from the tool body, for accepting uphole flowof the fluid stream including entrained wellbore debris; and acartridge, insertable into the tool body, including a cartridge centralfluid passageway and a plurality of cartridge Venturi nozzle tubesdistributed around the lateral circumference of the cartridge, whereineach Venturi nozzle tube is fluidly connected to one of the plurality oftool body exit ports, the cartridge Venturi nozzle tubes for providingsuction inside the cartridge, drawing the fluid stream up from thecollection chamber, into the cartridge central fluid passageway, throughthe cartridge Venturi nozzle tubes and through the tool body exit portsinto an annular space of the wellbore; drawing the fluid streamincluding entrained wellbore debris upward through the collectionchamber; passing the fluid stream from the work string and the fluidstream from the collection chamber into the annular space of thewellbore.